The “Dirigibile Italia” base in Ny-Ålesund. In the red box the antenna of the GNSS receiver (INGV). Photo by V. Romano and G. De Franceschi ©INGV
The ionosphere can have electron density irregularities which can cause diffraction and scattering of radio signals passing through it. The fluctuations of satellite signals in both amplitude and phase are called ionospheric scintillation. Ionospheric scintillation can cause serious problems to satellite signals, compromising, for example, the quality of the solutions provided by navigation systems. The ionosphere can deviate from the expected behavior predicted by the models. This happens, for example, when the ionosphere includes irregularities within it, areas in which the electronic density clearly differs from that of the surrounding environment. These irregularities can cause diffraction, i.e. scintillation, effects on the signals passing through them. The formation, evolution and dynamics of these irregularities are determined by the interaction between the geomagnetic field, the ionospheric currents, the interplanetary magnetic field (IMF) and the solar wind (i.e. the flow of energetic particles coming from the Sun) and are the manifestation of different physical phenomena depending on the latitude at which they occur. Ionospheric scintillations are more present in low and high latitude areas.
To monitor transient effects such as ionospheric scintillations it is necessary to use GPS receivers capable of sampling the signal both in amplitude and phase with a frequency of at least 50Hz. As part of its monitoring and Space Weather activities, INGV has created a network of GISTM receivers (“GPS Ionospheric Scintillation and TEC Monitors”) capable of providing real-time information on ionospheric scintillations. The GISTM system is based on receivers capable of providing useful indices for the study of scintillations on signals at different frequencies emitted by satellites of different GNSS (Global Navigation Satellite Systems) constellations and the TEC (Total Electronic Content) value. Currently the network, continuously updated, consists of receivers installed in the Svalbard Islands (Norway), in Antarctica, on the island of Lampedusa (Italy) and in Sao Paolo (Brazil). The first GISTM was installed in September 2003 at the Italian arctic station "Dirigibile Italia" in Ny Alesund (79,9° N, 11,9° E, Svalbard, Norway).
Real-time data http://eswuax.rm.ingv.it/